Distance-based degrees of polarization for a quantum field

Journal Article · Thu Sep 15 04:00:00 EDT 2005 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.72.033813· OSTI ID:20718621

Klimov, A B ^[1]; Sanchez-Soto, L L; Yustas, E C ^[2]; Soederholm, J ^[3]; Bjoerk, G ^[4]

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1. Departamento de Fisica, Universidad de Guadalajara, 44420 Guadalajara, Jalisco (Mexico)
2. Departamento de Optica, Facultad de Fisica, Universidad Complutense, 28040 Madrid (Spain)
3. Institute of Quantum Science, Nihon University, 1-8 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan)
4. School of Information and Communication Technology, Royal Institute of Technology (KTH), Electrum 229, SE-164 40 Kista (Sweden)

It is well established that unpolarized light is invariant with respect to any SU(2) polarization transformation. This requirement fully characterizes the set of density matrices representing unpolarized states. We introduce the degree of polarization of a quantum state as its distance to the set of unpolarized states. We use two different candidates of distance, namely the Hilbert-Schmidt and the Bures metric, showing that they induce fundamentally different degrees of polarization. We apply these notions to relevant field states and we demonstrate that they avoid some of the problems arising with the classical definition.

• OSTI ID: 20718621
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 72; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ALGEBRA
DENSITY MATRIX
DISTANCE
ENERGY LEVELS
OPTICS
POLARIZATION
QUANTUM MECHANICS
SU-2 GROUPS
TRANSFORMATIONS
VISIBLE RADIATION